RENTON — Tackle James Carpenter and guard John Moffitt were the Seahawks' first two picks in the April draft, a pair of offensive linemen chosen to become the bedrock of Seattle's rushing attack.

Their lockers are right next to each other. So are their numbers: Carpenter wears No. 75, Moffit No. 74.

This week, they are united by misfortune, each suffering a season-ending knee injury. Moffitt was injured during the first quarter of Sunday's victory over Baltimore; Carpenter during a blocking drill in practice Wednesday. Moffitt's medial collateral and post collateral ligaments were damaged; Carpenter's anterior cruciate ligament was torn.

Both will require surgery, and neither will play again this season — losses that are especially difficult for a rebuilding team.

"It's tough on them, because every day they do something that is part of their development," said offensive line coach Tom Cable. "The offseason would be valuable for them, as would the second half of the season. So we're going to lose all that, but once we get them back next spring, we'll go back to work and kind of catch 'em up."

Pardon Cable if he doesn't participate in the wringing of hands over how this affects Seattle's future. The Seahawks have a game on Sunday in St. Louis, and he has to get Paul McQuistan ready to start at right guard and Breno Giacomini at right tackle.

Injuries are part of the NFL. Just look at Seattle's opponent this week — the Rams have 11 players on injured reserve, tied for third-most in the league.

Just this week, the Rams lost cornerback Al Harris to a knee injury. Harris was only signed after the losses of cornerbacks Bradley Fletcher and Ron Bartell earlier in the season.

But there is something so incredibly unfortunate and downright fluky about Carpenter's injury that it merits pause. The first-round pick was hurt during a one-on-one drill that is among the most basic for an offensive lineman. It's an exercise he has done perhaps a thousand times this year alone, a drill that Cable has coached for 25 years,

"I've never lost a guy in a (pass-protection) drill," Cable said.

The fact it came four days after the injury to third-round pick Moffitt only compounds the concern, because Seattle's offensive line seemed to be turning the corner.

Through seven games, the Seahawks had allowed a league-high 28 sacks and were averaging the second-fewest rushing yards in the league. In the past two games, against well-regarded defenses, the Seahawks allowed just two sacks and had running back Marshawn Lynch rush for his two highest single-game totals in the regular season since becoming a Seahawk.

"I felt like we were on the right path," Cable said.

And now?

"We move forward," he said. "We don't change who we're trying to become or what we're trying to accomplish for our offense and for this football team. We don't back down, we just go forward."

McQuistan becomes the starting guard. A third-round pick by Oakland in 2006, he played three seasons with the Raiders under Cable. McQuistan started three games for Seattle earlier this season when Robert Gallery was out with a groin injury.

Giacomini moves in at right tackle. A fifth-round pick by Green Bay in 2008, the Seahawks signed him off the Packers' practice squad last year. He started the regular-season opener at right tackle this season as Carpenter filled in at left guard.

"We have two guys that have proven they can play," said center Max Unger. "We're not going to let this slow us, the progress we've had in the run game or as a group."

That doesn't make the losses Seattle suffered along the line the past week any less inexplicable, though.